SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5ee8ad272d03fb29d35822d321f78bd3eff5762e08bfad2ecbe180a19122193' 
  AND token = 'rmg06aqGk1b7GQwXd1mjmhqevB40nuiKDqRoBugaA+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}